RB25 Valvetrain Questions.

Post by **Chaos the Xile** » Thu Dec 06, 2007 1:11 am

I'm looking to purchase a set of valvesprings in the near future for my S1 RB25. I've looked at the Tomei's but they seem to only be a single spring. I really want a dual spring system, since I'm going to be shooting for 600+WHP. Does anyone know of a brand that makes a duel spring valvespring, or if aftermarket RB26 springs will work w/o any or little modification?

Next is the Camshafts. I am strongly leaning toward the Tomei PROCAMS, since they will most likely be a better choice of cam for my power goals. When converting to a cam w/ this high of lift and duration will I also need to purchase a set of the Tomei Soild type lifters to replace the stock hydrolic ones?

Post by **StricNyne** » Thu Dec 06, 2007 4:02 am

ahh cams i am in your boat... i heard rb26 will work but its gunna require an entire rb26 head and yadda be super expensive.... i have yet to find dual springs for rb25 BUT supertech said they MIGHT make some, as far as the procams, you need to machine head to clear the cams on top of that you need solid lifter conversion but that sas far as i can find information about it.. personally i decideed to source a NEO head which already has solid lifters, and can be gotten for around 500 dollers, it will bolt up to a non neo block , but it will raise yer compression due to smaller combustion chambers, with that you can get drop in tomei procams. honestly the aftermarket area for non neo heads SUCKS, idk if rb26 and neo head components are interchangable, so i just picked up a set of tomei valve springs for the mean time to prevent valve float and called it a day, also on non neo after like 256 duration cams u lose vtc and i heard on neo it wont effect the VVT, but u need something to control the VVT sigh its a headache, but i think for my self i will just get a neo head, tomei head parts (valve springs and cams) and call it a day

Post by **Darius** » Thu Dec 06, 2007 4:22 am

High lift does not necessarily have anything to do with the type of lifter. The type of lifter determines the type of cam lobe shape. Also, I'm not seeing the purpose of dual springs on the valve springs. The odds of you floating a valve on stiffer single springs at 600 hp are low. Unless, that is, you are trying to get 600hp out of the stock turbo and revving the thing up to 10,000 rpms.

You can convert to a solid lifter setup if you want. I wish I would have gone that direction with my build, but you live and learn. Ferrea sells the NEO kit with valves, springs and retainers. (NOT cheap!) The only thing you would need to change is the type of cam to a solid lifter type. I don't know how a NEO cam would fit on a S1/S2 head, but it has probably been done by some Aussies.

And if you want high lift pro cams >9.0mm you can do your machine work while you have the head apart and you are waiting on Ferrea.

Post by **StricNyne** » Thu Dec 06, 2007 4:34 am

ferrea charges like 1k for just valves iirc i rather spend 500 and get solid lifters too with neo head !!!

Post by **Darius** » Thu Dec 06, 2007 4:48 am

My Ferrea valves only cost $484 shipped.

Post by **Coolwhip** » Thu Dec 06, 2007 4:53 am

hey Daris, lets not go there. We know it cost ya more than just that. Not with cash, but with headaches

just messing with ya bud.

Post by **Darius** » Thu Dec 06, 2007 5:33 am

HAHAHAHA yeah it did. But if you are going with the solid lifter conversion, I don't think you'll run into the issues that I did since their stock valves are for the NEO.

Post by **StricNyne** » Thu Dec 06, 2007 5:38 am

yeah what i wanna do is buy a neo head, get it machine , and build it up then just take off old head, put new head on, but thats a WAYS off i need a running car first... i think thats cheaper than building my head up in long run

Post by **Chaos the Xile** » Thu Dec 06, 2007 8:22 am

ok, well with a little searching i founds Ferrea Dual Valve Springs, Retainers on horsepowerparts.com. i'm gonna call them and make sure they are for the Rb25, and can still get them.

Stricnyne, where were you looking into buying a NEO RB25 Head from?

Post by **Darius** » Thu Dec 06, 2007 8:52 am

Make sure they are for the right RB25 though because the S1/S2 valves are considerably shorter than the NEO's and I would imagine the springs are as well. It depends on the lifter you use.

Post by **Chaos the Xile** » Thu Dec 06, 2007 9:37 am

Darius wrote:My Ferrea valves only cost $484 shipped.

Are they the stainless stel vavles? And could you still get this price on the valves you have?

Post by **Bluefire** » Thu Dec 06, 2007 10:05 am

The springs are really dependent on how high you want to rev not on power goals. Most aftermarket single springs are strong enough to 8,000 maybe even 9,000 rpm. And at that rpm your gonna need solid lifters for sure...

-Bluefire

Post by **Chaos the Xile** » Thu Dec 06, 2007 10:23 am

I'm looking to rev anywhere between 8-8,500RPMS

Post by **Darius** » Thu Dec 06, 2007 11:16 am

Bluefire wrote:The springs are really dependent on how high you want to rev not on power goals. Most aftermarket single springs are strong enough to 8,000 maybe even 9,000 rpm. And at that rpm your gonna need solid lifters for sure...

-Bluefire

Even Bluefire is backing me up on that one.

For 8500 rpms, you need solid lifters. For 8000 rpms, you can get by with the stock hydraulic lifters.

Post by **Chaos the Xile** » Thu Dec 06, 2007 12:47 pm

ok so solid lifters it is, i'll add that to my "want but not getting for christmas" list. ummm... with the solid lifters can I run the Poncam, or do I have to use the procams with them?

Post by **Cjmartz2k** » Thu Dec 06, 2007 12:50 pm

I run it to 8k with 500+hp on a completely stock head (and motor for that matter). I kinda falls flat after 7.5k/7.7k anyways though. What is the point of wanting to rev it that high?

Post by **Chaos the Xile** » Thu Dec 06, 2007 11:56 pm

Cjmartz2k wrote:I run it to 8k with 500+hp on a completely stock head (and motor for that matter). I kinda falls flat after 7.5k/7.7k anyways though. What is the point of wanting to rev it that high?

Thats on a completely stock head too, after a valve and port job I'm sure it will flow over 8K.

Post by **Darius** » Fri Dec 07, 2007 4:21 am

Yup.

Poncams are less aggressive cams compared to the Procams. The name difference has nothing to do with whether they are for solid or hydraulic lifters. Just make sure the cam you get matches the lifters you use.

Post by **StricNyne** » Fri Dec 07, 2007 6:27 am

i thought rb25 procams only cam with solid lifters, i think HKS made more aggressive to use w/o solid lifters cams for rb25 are PITA rb26 head has like 10x more options

Post by **Chaos the Xile** » Fri Dec 07, 2007 10:33 am

StricNyne wrote:i thought rb25 procams only cam with solid lifters, i think HKS made more aggressive to use w/o solid lifters cams for rb25 are PITA rb26 head has like 10x more options

Yeah i think its the HKS 264 cam. So I can use the Tomei Solid Lifters and Poncam combination? Darius what other theys of solid lifters does tomei offer? i thought they only provided one set.

Post by **Darius** » Fri Dec 07, 2007 10:50 am

Solid lifter link:http://www.tomei-p.co.jp/_2003...html

Factory camshaft specs:http://www.tomei-p.co.jp/_2003....html

Tomei camshaft specs:http://www.tomei-p.co.jp/_2003....html

Note: Lash refers to auto lash adjusters = hydraulic liftersSolid refers to solid lifters, DUR

Post by **Chaos the Xile** » Sat Dec 08, 2007 11:44 pm

Cool thanks Darius, Solid Lifters, Poncams, and Valve Springs.

RB25 Valvetrain Questions.

RB25 Valvetrain Questions.

Re: RB25 Valvetrain Questions. (Chaos the Xile)

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